1. Field of the Invention
The present invention relates generally to a field emission device, and more particularly to a field emission device capable of preventing generation of a leakage current due to an electrical shortage between a gate electrode and an emitter, which is generated by a high operating voltage.
2. Description of the Prior Art
A field emission device is used in a field emission-type display device, etc. The field emission-type display device is a device for which a research has been made as a next-generation flat panel display device following TFT-LCD.
The field emission device is mainly divided into a triode type and a diode type. The triode type includes a cathode having the emitter and the gate electrode, and an anode installed on the cathode. The emitter serves to emit electrons and is usually made of a tip shape. The gate electrode serves to control the amount of electrons generated from the emitter depending on the voltage applied thereto. The diode type has only one electrode at the cathode.
The present invention relates to a triode-type field emission device. A conventional triode-type field emission device will be below described.
FIG. 1 shows a conventional field emission device.
Referring now to FIG. 1, the conventional field emission device includes an emitter 104 for emitting electrons and made of a tip shape, a gate electrode 105 for controlling the amount of electrons generated from the emitter 104 depending on the voltage applied thereto, and an anode 107 positioned above the gate electrode 105, as a main component. The anode 107 is connected to the anode terminal 108 and the gate electrode 105 is then connected to the gate terminal 106.
Meanwhile the emitter 104 is connected to the switching means 103 for selectively supplying current to the emitter 104. The switching means 103 consists of a transistor and selectively supplies current from the source electrode 101 to the emitter 104 depending on the voltage applied to the gate electrode 102 of the transistor.
As shown in FIG. 1, the gate electrode 105 of the field emission device is formed around the emitter 104. A high voltage for discharging electrons from the emitter 104 is applied to the gate electrode 105. At this time, when the emitter 104 and the gate electrode 105 are electrically connected, sufficient difference of voltage between the emitter 104 and the gate electrode 105 is not formed to not only discharge electrons but also generate a leakage current. Thus, the power consumption is rapidly increasing.
Also, if the gate electrode 105 of the field emission device is connected to a gate, source or drain of a transistor due to electrical reason or process reason, sufficient difference of voltage between the emitter 104 and the gate electrode 105 of the field emission device is not formed to normally discharge elections while a leakage current is formed in a similar fashion.
If the leakage current is flowed as above, the difference in the voltage between the emitter 104 and the gate electrode 105 of the field emission device is accordingly reduced. The reduced amount is proportional to the multiplication of the leakage current and resistance. Therefore, as a sufficient voltage is not applied to the gate electrode 105 of the field emission device formed around a region where the leakage current is generated, a normal operation could not be performed.
Due to this, there are problems that the power consumption is increased and reliability of the device is degraded.
The present invention is contrived to solve the above problems. An object of the present invention is therefore to provide a field emission device capable of preventing increase of the power consumption and improving reliability of the device.
Another object of the present invention is to provide a field emission device comprising a gate electrode, an emitter, an anode, and a resistance element connected between the gate electrode and an external terminal to preventing a leakage current to the gate electrode or the emitter. The resistance element may use a resistor or a metal wiring a portion of which is thinly formed and thus has a high resistance.